Linear theory of uncompensated thermal blooming in turbulence

Technical Report · Tue Feb 07 04:00:00 EST 1989

DOI:https://doi.org/10.2172/6066251· OSTI ID:6066251

Chambers, D. H.; Karr, T. J.; Morris, J. R.; Cramer, P. G.; Viecelli, J. A.; Gautesen, A. K.

A linearized theory of small perturbations in thermal blooming gives a surprisingly accurate description of the initial evolution of a plane wave propagating through an absorbing fluid medium. In the case of constant absorption and fluid velocity, a sinusoidal perturbation of the optical field grows quasi-exponentially at a rate determined by its Fresnel number and the accumulated OPD due to blooming. Perturbations with small transverse length scales grow more rapidly than those with large length scales. The evolution of the optical spectrum and Strehl ratio in the presence of optical turbulence is accurately described. The growth of the small scale fluctuations eventually leads to a drop in Strehl. More complicated cases with varying absorption and velocity profiles can be formally analyzed using a WKB approximation. Numerical simulations show growth suppression when the velocity varies along the optical path. These predictions from the linearized theory agree well with results from numerical simulations of the full nonlinear system and thus provides a standard for comparing different numerical codes. 12 refs., 9 figs.

• Research Organization: Lawrence Livermore National Lab., CA (USA)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6066251
• Report Number(s): UCID-21696; ON: DE89014604
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420300 -- Engineering-- Lasers-- (-1989)
640410* -- Fluid Physics-- General Fluid Dynamics
656003 -- Condensed Matter Physics-- Interactions between Beams & Condensed Matter-- (1987-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BEAM OPTICS
CHEMICAL ANALYSIS
DIFFERENTIAL EQUATIONS
ELECTROMAGNETIC RADIATION
EQUATIONS
LASER RADIATION
MATHEMATICAL MODELS
NONDESTRUCTIVE ANALYSIS
PARTIAL DIFFERENTIAL EQUATIONS
RADIATION ABSORPTION ANALYSIS
RADIATIONS
TURBULENCE
WAVE EQUATIONS
WAVE PROPAGATION